Axially arranged rotary threshing or separating systems have long been in use in agricultural combines for threshing crops to separate grain from crop residue, also referred to as material other than grain (MOG). Such axially arranged systems typically include at least one cylindrical rotor rotated within a cage or concave, with the rotor and surrounding concave being oriented so as to extend forwardly to rearwardly within the combine. During operation of the combine, crop material is fed or directed into a circumferential passage between the rotor and the concave and is carried rearwardly along a generally helical path through such passage by rotation of the rotor as grain is threshed from the crop material. The flow of crop residue remaining between the rotor and concave after threshing is typically discharged or expelled at a rear or downstream end of the rotor. After discharge from the threshing system, the crop residue is typically directed into a crop residue distribution system located below and rearwardly of the rear end of the rotor. The crop residue distribution system typically includes a chopper assembly that conveys and/or chops and propels the residue rearwardly towards an area within the rear end of the combine, hereinafter referred to as a distribution chamber. The crop residue provided within the distribution chamber may either be discharged therefrom onto a field as a windrow or be directed into a chopper and/or spreader mounted on or at the rear end of the combine that is operable to spread the residue over a swath of a field.
Typically, the chopper assembly of a crop residue distribution system is configured to perform two primary functions: (1) chop the crop residue so that is can decompose quickly; and (2) convey the crop residue to the rear end of the combine. When it is desired to chop the crop residue and spread the resulting material back into the field, the chopper assembly is typically rotated at a high speed, which allows the chopper assembly to efficiently perform both of its functions. However, it is often desired to not chop the crop residue and, instead, collect it for baling. In such instances, the chopper assembly must be operated at a relatively low sped to prevent the crop residue from being chopped. Such low speed operation can negatively impact the ability of the chopper assembly to convey the crop residue towards the rear end of the combine, particularly when the chopper assembly corresponds to a flail chopper assembly having a plurality of flail blades pivotally coupled to a corresponding rotor shaft. With such chopper assemblies, the rotation of the rotor shaft at the low speed required to prevent chopping of the crop residue typically does not create enough force to maintain the flail blades at their extended, radially oriented position. As such, the flail blades tend to pivot backward during low speed operation, which significantly impacts the operating efficiency of the chopper assembly.
Accordingly, an improved flail chopper assembly for use within a crop residue distribution system of an agricultural combine that addresses one or more of the issues described above would be welcomed in the technology.